Try use option Freestyle in script for Blender
You are close, the use of bpy.types.FreestyleLineSet is wrong as this refers to the class definitions used elsewhere. The correct way to add a new lineset is freestyle.linesets.new('mylineset'), you also have a typo in linestyle.visiblity = 'RANGE'

A working version of your example is 

import bpy

sceneR = bpy.context.scene
freestyle = sceneR.render.layers.active.freestyle_settings

linestyle = freestyle.linesets.new('mylineset')
sceneR.render.use_freestyle = True
sceneR.svg_export.use_svg_export = True
freestyle.use_smoothness = True
freestyle.use_culling = True
linestyle.select_by_visibility = True
linestyle.select_by_edge_types = True
linestyle.visibility = 'RANGE'
linestyle.select_silhouette = True